Lectin-cytochemical study on epithelial mucus glycoprotein of conjunctiva and pterygium

The epithelium of pterygium and conjunctiva was studied with reference to cytochemical reactivity to six fluorescein-labeled lectins that recognize a certain carbohydrate residue(s) of cellular membrane-bound or secretory glycoprotein: Ulex europaeus agglutinin-1 (UEA-1, specific for fucose); Dolichos biflorus agglutinin (DBA, specific for N-acetylgalactosamine); peanut agglutinin (PNA, specific for galactose-beta 1-3N-acetylgalactosamine): wheat germ agglutinin (WGA, specific for N-acetylglucosamine and N-acetylneuraminic acid); Concanavalia ensiformis (Con A, specific for mannose); Ricinus communis agglutinin-1 (RCA-1, specific for galactose). Non-goblet epithelial cells of pterygium were labeled with UEA-1, DBA and PNA, while those of conjunctiva were not. Distribution density of goblet cells was larger in pterygium than in conjunctiva, but there was no distinct difference in lectin reactivity between the two tissues, with marked label with WGA, PNA and RCA-1. Con A did not bind to either pterygium or conjunctiva. The observations suggest the presence of anomalous mucus glycoproteins secreted from pterygium.